Endoscope and endoscopic instrument system having reduced backlash when moving the endoscopic instrument within a working channel of the endoscope

ABSTRACT

An endoscopic instrument has a portion having an outer surface with a non-circular cross-sectional shape. The non-circular cross-sectional shape may be provided to the instrument by providing peripheral projections or fins along the length of the portion or by providing the periphery of the portion with a polygonal shape. Where fins are used, the fins are preferably quite small and only have a minimal effect on the fluid flow cross sectional area between the interior of the working channel and the endoscopic instrument. The resulting instrument has significantly reduced backlash while maintaining adequate fluid flow in the working channel. According to a second embodiment of the invention, a portion of the interior of the working channel of the endoscope has an interior surface having a non-circular cross sectional shape by the inclusion of a plurality of radially spaced and inwardly directed ribs or by being polygonally shaped. The resulting endoscope reduces the backlash of an endoscopic instrument inserted therein while maintaining adequate fluid flow in the working channel.

CROSS REFERENCE OF CO-PENDING APPLICATIONS

This application is a continuation of co-pending U.S. application Ser.No. 10/214,005, filed Aug. 7, 2002, which is a continuation of U.S.application Ser. No. 09/418,246, filed Oct. 14, 1999, now U.S. Pat. No.6,454,702, both disclosures of which are incorporated herein byreference.

FIELD OF THE INVENTION

This invention relates broadly to surgical instruments. Moreparticularly, this invention relates to an endoscope and endoscopicsurgical instruments adapted to be extended into a channel of theendoscope.

STATE OF THE ART

At the present time there are many instruments made for use inendoscopic medical procedures. Typically, endoscopic instruments arelong and flexible cylindrically tubular devices with manually operatedhandles at their proximal ends and tissue-manipulative cutting,grasping, injecting, or cautery components at their distal ends. Suchinstruments are introduced into a flexible endoscope which is insertedinto the patient through a natural or surgically-created opening. Theendoscope includes an elongate portion defining several lumenstherethrough and a proximal handle for directing the elongate portion.At least one lumen is provided with an optical imaging system, e.g., ascope, and several lumina or “working channels” are typically providedfor extending endoscopic instruments therethrough. The working channelof the endoscope typically consists of a PTFE-lined cylindrical tubepassing from the proximal (handle) end of the endoscope to its distal(working) end. Working channels are typically 2 to 4 millimeters ininside diameter.

During the medical procedure, the doctor passes one or more endoscopicinstruments through the working channels in order to manipulate thetissue being visualized by the optical system of the endoscope. Usuallythe doctor must repeatedly manipulate the distal end of the instrumentby manually pushing and pulling on the proximal portion of the tubularshaft of the endoscopic instrument near where the shaft enters thehandle of the endoscope.

The view through an endoscope is highly magnified when seen on the videomonitors typically used for these procedures; a field of view that maybe a few millimeters across would be enlarged to several inches on thevideo screen. Accordingly, the instrument must be moved very preciselyin very small increments in order to approximate and treat the tissuebeing visualized. In fact, the doctor must position the distal tip ofthe endoscopic instrument within a fraction of a millimeter of thedesired location in order to achieve desired results. However, becauseof friction and backlash in the way the instrument passes through theendoscope, achieving this level of accuracy is difficult. For example,an endoscope several feet long may be positioned in the colon of apatient with the distal end of the endoscope tightly reflexed tovisualize a particular area of the ascending colon. In such a position,the endoscope is bent into a very sinuous shape in multiple planes.Since the outside diameter of the endoscopic instrument is significantlysmaller (e.g., 2.2 mm) than the inside diameter of the working channel(e.g., 3.2 mm), a large clearance space exists between the instrumentand the channel. When the instrument is pulled back, the tension on theinstrument causes the instrument to be pulled taut and the instrumentnaturally assumes the shortest path through the channel. When theinstrument is pushed forward, friction causes it to assume the longestpath through the channel (that is, the shaft of the instrument must“fill” the working channel before the distal end of the instrumentbegins to move). As a result, quite a bit of backlash (lost motion) isexperienced by the doctor when the doctor tries to manipulate the distalend of the instrument. If it is necessary to pull the tip back a bit,the backlash must first be pulled out before the distal end can beretracted. If the doctor pulls the instrument back a little too far, thedoctor must then push it several millimeters forward before there is anymotion at all at the distal end. During this manipulation, theendoscopic instrument alternately assumes the longest-path andshortest-path positions within the working channel of the endoscope. Ifthis backlash can be reduced or eliminated, the manipulation of thedistal end of the endoscopic instrument can be made much easier and morepositive, and the doctor can achieve his desired positioning morerapidly. However, this is not a simple problem to overcome for severalreasons.

While the backlash situation described above can be reduced orsubstantially eliminated if the clearance between the outside of theendoscopic instrument and the inside of the working channel of theendoscope can be reduced, this is not a practical solution. It is oftennecessary to inject fluid (or to operate suction) through the annularspace between these two structures. If the instrument shaft were tosubstantially fill up the space within the working channel, the backlashwould be reduced, but there would be greatly reduced ability to conductfluid through the working channel around the instrument. In fact,because of the nature of fluid flow, as the aspect ratio of the annularclearance space (the ratio of the thickness of the fluid channel to itscircumferential length) becomes small, the impedance to fluid flow growsdisproportionately to the reduction in cross-sectional area of the fluidpassage.

In addition, as the diameter of the shaft approaches the inside diameterof the working channel, the area of contact between the instrument andthe working channel becomes larger, particularly since the workingchannel is usually made of a relatively soft material, PTFE. Thisincrease in contact area between these parts results in an increase infrictional drag on the instrument when the doctor attempts to move itthrough the channel.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide an endoscopicsystem with little or no backlash between the endoscope and theendoscopic instrument.

It is also an object of the invention to provide an endoscopic systemwhich reduces the backlash between an endoscopic instrument in a workingchannel of an endoscope, while maintaining open area therebetween forpermitting fluid flow.

In accord with these objects, which will be discussed in detail below,an endoscopic system is provided where either a portion of theendoscopic instrument or a portion of the working channel is providedwith a non-circular cross-section.

Generally, an endoscopic instrument includes an elongate flexibletubular member having proximal and distal ends, a control member havingproximal and distal ends and extending through the tubular member, anend effector assembly coupled to the distal ends of the tubular memberand the control member, and a handle means for moving the control memberrelative to the tubular member to operate the end effector assembly.According to a first embodiment of the invention, the distal end of theelongate flexible tubular member of the endoscopic instrument has anouter surface having a non-circular cross-sectional shape. Thenon-circular cross-sectional shape may be provided to the portion of thetubular member by radially spacing a plurality of fins or otherprojections about the peripheral (exterior) of the portion, or byproviding the portion with a polygonal cross-sectional shape. Where finsare provided, the fins can be quite small and will only have a minimaleffect on the fluid-flow cross-sectional area between the workingchannel and the endoscopic instrument. Thus, the resulting endoscopicinstrument will have significantly reduced backlash while maintainingadequate fluid flow in the working channel. In addition, the fins orcomers of the polygonal shape provide few and relatively small contactpoints so that the endoscopic instrument may be readily advanced throughthe lumen (working channel) of an endoscope.

According to a second embodiment of the invention, an endoscope isprovided having a proximal handle, and elongate flexible distal portionhaving an imaging channel provided with an imaging system and a workingchannel having an interior surface and adapted to receive an endoscopicinstrument therethrough. The working channel along its length has apreferably substantial portion at which the working channel has anon-circular cross-sectional shape. The non-circular cross-sectionalshape can be provided to the working channel by providing the interiorsurface of the working channel with a plurality of radially spaced andinwardly directed ribs or other projections or by providing the interiorsurface of the working channel with a polygonal shape. The ribs can bequite small and will only have a minimal effect on the fluid flow crosssectional area between the working channel and the endoscopicinstrument. Therefore, the resulting endoscope will reduce the backlashof an endoscopic instrument inserted therein while maintaining adequatefluid flow in the working channel. Additionally, the endoscopicinstrument can be readily advanced through the working channel, as therewill be few and relatively small contact points between the two.

Additional objects and advantages of the invention will become apparentto those skilled in the art upon reference to the detailed descriptiontaken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross sectional view of an endoscopicinstrument according to the invention;

FIG. 2 a is an enlarged cross-section across line 2-2 in FIG. 1according to a first embodiment of the invention;

FIG. 2 b is an enlarged cross-section across line 2-2 in FIG. 1according to an alternative first embodiment of the invention;

FIG. 3 is a side elevation of an endoscope according to the inventionshown provided with an endoscopic instrument according to the invention;and

FIG. 4 is an enlarged cross-section across line 4-4 in FIG. 3,illustrating several working channel-endoscopic instrument systemsaccording to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to FIG. 1, an endoscopic instrument 10 for insertion througha working channel of an endoscope is shown. According to a firstembodiment of the invention, the endoscopic instrument 10 includes anactuation handle 12, a tubular coil 14, a jacket 16 provided about atleast a distal portion 18 of the coil 14, an end effector assembly 20,e.g., a biopsy forceps, and a control wire 22. The actuation handle 12typically includes a stationary member 26 and a displaceable spool 28.The stationary member 26 includes a distal throughbore 30, a centralslot 32, and a proximal thumb ring 34. The displaceable spool 28 isslidably disposed on the stationary member 26 and has a cross member 36which passes through the slot 32. The proximal end of the control wire22 is coupled to the spool 28. Operation of the actuation handle 12 isdescribed fully in U.S. Pat. No. 5,228,451 to Bales, which is herebyincorporated by reference herein in its entirety. In brief, longitudinalmovement of the spool 28 within the slot 32 results in operation of theend effector assembly 20; i.e., the end effector assembly moves betweenopen and closed positions.

Referring now to FIG. 1 and 2 a, in accord with the first embodiment ofthe invention, the jacket 16 is a low friction coating or sheath,preferably made from PTFE, extending over at least a distal portion ofthe coil 14. The jacket 16 may be extruded over the portion of the coil,or may be provided as an attachment capable of being provided over anassembled endoscopic instrument. For example, the jacket may be atubular member having a longitudinal slit. The jacket 16 definesseveral, e.g., five, longitudinal fins 30 radially spaced about thecoil. By way of example, and not by limitation, for an endoscopicinstrument intended to be inserted into an endoscope having a workingchannel of 3.2 mm inside diameter, the jacket 16 is preferably acylinder 2.2 millimeters in diameter with thin fins (or lands) having athickness of approximately 0.1 mm and extending approximately 0.4 mm outfrom the coil surface. Such a construction would almost completely fillthe diameter of the working channel of the endoscope (i.e., the radialdimension of the jacket, from the center of the coil 14 out to the endof a fin 30, is nearly equal to the radius of the working channel),substantially reducing the motion backlash. However, since the fins 30are quite thin, only a small amount of the fluid-flow cross sectionalarea would be sacrificed. Additionally, the number of the contact pointsand surface area of contact points between the fins and the interior ofthe working channel is substantially minimal.

It is also preferable that the fins extend along only a distal portionof the endoscopic instrument rather than along the entire length of theendoscopic instrument. If the fins 30 were to extend to the mostproximal portion of the coil 14, it would be difficult to effect a fluidseal against the shaft of the instrument where the coil enters theendoscope handle. Such a seal is needed if fluid is to be injectedthrough the working channel. Since the majority of the flexing of theendoscope in an endoscopic procedure takes place at the distal portion,where the endoscope is situated inside the patient, the majority ofmotion backlash results from the looseness of the instrument in thedistal portion of the endoscope. Accordingly, it is preferable for thefins 30 to be placed on only the corresponding distal portion 18 of theendoscopic instrument 10 (for example, on the distal 150 cm of a 240 cminstrument) while leaving the proximal portion (i.e., 90 cm) a smoothcylinder. Such an endoscopic instrument would then have greatly reducedmotion backlash when manipulated by the physician, and it would allowsubstantially unimpeded fluid flow through the working channel of theendoscope while providing an easily sealed-upon surface where theinstrument exits the endoscope handle.

Turning now to FIG. 2 b, according to an alternate first embodiment ofthe invention, the jacket 16 b has a non-circular cross-sectional shapeover the coil 14 b such that the cross-sectional shape is generallypolygonal. For example, the jacket 16 b may have a pentagonal shape, asshown. By way of example, and not by limitation, for an endoscopicinstrument intended to be inserted into an endoscope having a workingchannel of 3.2 mm inside diameter, the corners 30 b of the polygonpreferably extend approximately 0.4 mm from the coil surface. Such aconstruction substantially completely fills the diameter of the workingchannel of the endoscope, substantially reducing the motion backlash,yet only contacts the working channel at the comers 30 b. In addition,space is provided between the sides of the jacket and the workingchannel for fluid-flow.

Referring now to FIGS. 3 and 4, an endoscope 110 according to a secondembodiment of the invention is shown. The endoscope 110 includes anelongate tubular portion 112 and a proximal handle portion 114 adaptedto manipulate and direct the distal end of the tubular portion 112. Thetubular portion 112 has a plurality of lumens, with one lumen 142provided for receiving an optical scope or camera device 144 (which maybe built therein), several lumen 146, 148, 150, 152 provided forreceiving control wires 154, 156, 158, 160 extending from the handleportion 114 through the tubular portion 112, and at least one, andpreferably several working channels 162, 164, 166, 168 for receivingendoscopic instruments 170 therethrough. For example, endoscopicinstruments 10, 10 b according to the first embodiment of the invention(as shown in FIGS. 2 a, and 2 b, respectively) may be provided inworking channels 166, 168. The working channels have proximal openingsin the handle portion 114. Other lumens 172, 174 may be provided forother purposes. Endoscopes are described in general in U.S. Pat. No.5,179,935 to Miyagi which is hereby incorporated by reference herein inits entirety.

According to the second embodiment of the invention, a portion of atleast one of the working channels 162 is provided with a non-circularcross-sectional shape. The non-circular cross-sectional shape may bemolded into the working channel or more preferably is provided by a lowfriction, e.g, PTFE, insert 180 preferably fixed within a distal portion118 of the working channel 162. The insert 180 includes a plurality ofradially spaced and radially inwardly directed longitudinal ribs 182.The ribs 182 can be quite small. For example, the ribs 182 may beapproximately 0.1 mm thick and have a radial length of approximately 0.5mm. Therefore, the ribs would have a minimal effect on the fluid flowcross sectional area between the working channel and the endoscopicinstrument, and also provide relatively small contact points between theworking channel and the endoscopic instrument.

According to an alternate second embodiment of the invention, a workingchannel 164 is provided with a polygonal cross-sectional shape. Thepolygonal cross-sectional shape may be provided to the working channel164 via an insert 184 or may be molded integrally into the workingchannel.

In each of the alternate embodiments, the working channel is adapted toprovide reduced backlash, while maintaining adequate fluid flow in theworking channel around the endoscopic instrument, and minimal contactbetween the endoscopic instrument and the working channel. In eachalternate embodiment, the non-circular cross-sectional shape of theworking channel may extend the entire length of the channel or a portionthereof.

There have been described and illustrated herein several embodiments ofan endoscope and endoscopic instrument system having reduced backlashwhen moving the endoscopic instrument within the working channel of theendoscope. While particular embodiments of the invention have beendescribed, it is not intended that the invention be limited thereto, asit is intended that the invention be as broad in scope as the art willallow and that the specification be read likewise. Thus, while aparticular biopsy forceps endoscopic instrument has been disclosed, itwill be appreciated that endoscopic instruments having other endeffectors, e.g., scissors, punches, needles, etc., can be provided withthe non-circular cross-section of the invention as well. Furthermore,while a PTFE has been disclosed for the jacket of the instruments andinsert for the endoscope, other low friction materials can be used aswell. Also, while a particular number of fins and ribs have beendisclosed, it will be appreciated that other numbers of fins and ribscan be used. Alternatively, one or spiral fins or ribs can be provided.Furthermore, projections other than fins can be used. Moreover, otherpolygonal shapes may be used for the jacket over the coil and theendoscope insert. Also, the coil and/or jacket may be substituted withanother tubular member having a non-circular cross-section. For example,the tubular member may be extruded with a polygonal shape or with fins.It will therefore be appreciated by those skilled in the art that yetother modifications could be made to the provided invention withoutdeviating from its spirit and scope as so claimed.

1. An endoscopic instrument, comprising: an endoscope having a workingchannel formed therein, the working channel defining an inside diameter;and an endoscopic instrument slidably disposed in the working channel,the endoscopic instrument including: a tubular member including a regionhaving a non-circular cross-sectional shape and a section having anoutside diameter that is substantially equal to the inside diameter ofthe working channel, a control member slidably disposed in the tubularmember with an end effector coupled to the control member; and a handledisposed adjacent a proximal end of the control member for controllingthe position of the end effector.
 2. The endoscopic instrument of claim1, wherein the tubular member includes a proximal portion and a distalportion and wherein the region having a non-circular cross-section shapeis disposed adjacent the distal portion.
 3. The endoscopic instrument ofclaim 2, wherein the proximal portion has a generally circularcross-sectional shape.
 4. The endoscopic instrument of claim 1, whereinthe region having a non-circular cross-section shape has a polygonalshape.
 5. The endoscopic instrument of claim 1, wherein the regionhaving a non-circular cross-section shape is defined by a sheathdisposed over a portion of the tubular member.
 6. The endoscopicinstrument of claim 5, wherein the sheath includes a plurality of finsextending therefrom.
 7. The endoscopic instrument of claim 1, whereinthe working channel includes a region having a non-circularcross-section shape.
 8. An endoscopic instrument system, comprising: anendoscope having a working channel, an inside surface defining a workingchannel, and an inside diameter defined within the working channel; anelongate tubular member slidably disposed in the working channel, thetubular member having an outside surface having a section with anoutside diameter that is substantially equal to the inside diameter ofthe working channel; wherein at least one of the inside surface of theendoscope and the outside surface of the tubular member includes aregion having a generally non-circular cross-sectional shape; a controlmember slidably disposed in the tubular member; an end effector coupledto the control member; and a handle disposed coupled the control wirefor altering the position of the end effector.
 9. The endoscopicinstrument of claim 8, wherein the inside surface of the endoscopeincludes the region having a generally non-circular cross-sectionalshape.
 10. The endoscopic instrument of claim 8, wherein the outsidesurface of the tubular member includes the region having a generallynon-circular cross-sectional shape.
 11. The endoscopic instrument ofclaim 8, wherein both the inside surface of the endoscope and theoutside surface of the tubular member include regions having a generallynon-circular cross-sectional shape.
 12. A medical device, comprising: afirst tubular member having an inside diameter and an inside wallsurface, the inside wall surface defining a channel through the firsttubular member; and a second tubular member slidably disposed in thechannel, the second tubular member including an outer surface having aregion with a non-circular cross-sectional shape and a section having anoutside diameter that is substantially equal to the inside diameter ofthe first tubular member, an inner surface defining a lumen through thesecond tubular member, and a shaft slidably disposed in the lumen. 13.The medical device of claim 12, wherein the second tubular memberincludes a proximal portion and a distal portion and wherein the regionhaving a non-circular cross-section shape is disposed adjacent thedistal portion.
 14. The medical device of claim 13, wherein the proximalportion has a generally circular cross-sectional shape.
 15. The medicaldevice of claim 14, wherein the region having a non-circularcross-section shape has a polygonal shape.
 16. The medical device ofclaim 13, wherein the region having a non-circular cross-section shapeis defined by a sheath disposed over a portion of the second tubularmember.
 17. The medical device of claim 16, wherein the sheath includesa plurality of fins extending therefrom.
 18. The medical device of claim13, wherein the working channel includes a region having a non-circularcross-section shape.
 19. A medical device, comprising: a first tubularmember having a working channel, an inside surface defining a workingchannel, and an inside diameter defined within the working channel; asecond tubular member slidably disposed in the working channel, thesecond tubular member having an outside surface having a section with anoutside diameter that is substantially equal to the inside diameter ofthe working channel; wherein at least one of the inside surface of thefirst tubular member and the outside surface of the second tubularmember includes a region having a generally non-circular cross-sectionalshape; a control member slidably disposed in the second tubular member;an end effector coupled to the control member; and a handle disposedcoupled the control wire for altering the position of the end effector.